Shoe last construction



May 4, 1965 c. J. HUNT I SHOE LAST CONSTRUCTION Filed March 13, 1965INVENTOR. Charles J. liuni BY A5'TY.

United States Patent Ofiice 3,181,186 SHOE LAST CGNSTRUQ'HGN Charles 5.Hunt, independence, Ky, assign-or to 'Vuiean Corporation, Cincinnati,Ghio, a corporation of Gino Filed Mar. 13, 1963, Ser. No. 264,885 1iaim. (Ci; 12-136) This invention relates to improvements in shoe lastsand is particularly directed to a novel shoe last construction whichmakes it practical to materially reduce the Weight of the last and hencefacilitate its handling by operators during the shoe making processesthereon.

It is presently customary to make shoe lasts of solid high densitypolyethylene which is commercially available as Marlex, Grex, Fortiflex,etc. to mention a few suitable plastic starter materials. Shoemanufacturers have generally approved such lasts because of their caseof hinge operation, the ease with which finished shoes are withdrawnfrom these lasts and their freedom from breakage and longer life incomparison with the conventional shoe lasts made of wood. A seriousdrawback to the universal use of plastic shoe'lasts is their relativelyheavier weight in comparison to wood lasts which causes an increase intransportation costs and creates serious handling problems throughoutthe shoe manufacturing processes thereon.

It is therefore the main object of this invention to provide a novelplastic shoe last construction that is considerably lighter than presentplastic lasts but which retains all the desirable characteristics ofwood and solid plastic lasts.

Another object of the invention is to provide a shoe last structureideally suited to the production of socalled hinge lasts that comprisetwo parts secured together for relative hinging action by means of acase hardened, over-center spring link.

A further object of this invention is to provide an extremely strong andrugged plastic shoe last that will be of light weight and yet have allthe desirable features or both wood lasts and the plastic shoe lasts.

Yet a further object of this invention is the provisions of a last bodymade of a structurally weak material having light weight characteristicsand the reinforcement of this body throughout its greatest stress areasby a substantially stron er device composed of a relatively heaviermaterial than the last body.

With these and other objects in view, the invention will be bestunderstood and appreciated from the fol-lowing description of apreferred embodiment of my shoe last structure selected for purposes ofillustration and depicted in the accompanying drawing, in w'hich:

FIG. 1 is a side elevational view t my shoe last construction shown inan intermediate step of its manufacture;

FIG. 2 is a fragmental, side elevational view of my shoe last structurealso in an intermediate, but later stage of manufacture, than the lastshown in FIG. 1, parts thereof being broken away and shown in section.

FIG. 3 is a section on line 33 of FIG. 2.

FIG. 4 is a side elevational view of my completed shoe last constructionwith the hinge hardware in position thereon, parts being broken away andshown in section.

FIG. 5 is a section on line 5-5 of FIG. 4.

or foamed oholorinated polyether, such materials being provided withcontrolled amounts of a. foaming agent to produce a foamed plastic blockhaving a density in the range of about 0.70, which is the same densityas wood from which acceptable lasts are presently made. Foaming agentsare well known in the art as well as the methods and procedures forproducing masses of foamed, thermo-setting plastic materials and neednot be detailed hereinj Sufiice it to say that the foamed,therrno-setting plastic materials utilized in producing the plasticblock drom which the last body, It was turned in a lath, or the like,produces a porous last 'body 19 having literally thousands of smallvoids throughout its mass which materially reduces the amount of plasticmaterial in a particular last body and hence results in a substantial rej duction in weight of the body over comparable lasts comwill have adensity substantially the same as a comparable last made of hardinaplewood.

With reference to FIG. 1 itwill be understood that the turned last body19 shown therein has further been formed into a fore or toe part 1-1 anda rear or heel part 12 by the prior formation of ahinge knuckle v13which divides the last body and provides mating surfaces.

around which the parts rotate from the extended shoe forming positionsof the parts shown in full lines in the drawing to a collapsed positionof the parts, indicated by the dotted lines in FIG. 4 of the drawings.Oversized holes 14 and 15 are tor-med laterally through the toe part 11and the heel part 12, respectively, ofthe last body '16 adjacent thehinge 13 and the heel part is further provided in its upper portion.with an enlarged, blind end hole 16 that is positioned at right anglesto the hole therein.

"Parts made from foamed plastic material are not as strong as solidmasses of the same material and thus areas therein that are to besubjected to the greatest stresses or strains tend to collapse and breakdown in use. With particular reference to the plastic shoe last 10 thesestress areas occur in the parts 1-1 and 12 around the hinge 13 andaround the last mounting area adjacent the upper portion of the heelpart. To strengthen and reintorce these areas in the foamed plastic lastbody 19 the oversize, laterialholes 14 and '15 and the hole 16 arefilled by driving thereinto solid plugs 17 (FIG. 1) composed of highdensity polyethylene, or other relatively strong material and fixingsaid plugs in their respective holes It is generally understood thatshoe lasts are forms by a suitable cement, or other fastening means.These solid plugs made of polyethylene have a density in the range of..960 which creates a strong plug material that r is stronger and isalsov much heavier than hard maplewood. Subsequently, and as indicatedin FIG. 2, the last parts are mounte'd in suitable jigs and binge pinholes 18 are drilled through the central portions of each plug to formsleeves 176 in the fore and heel part, respectively, it being noted thatthe exact distance between the two hinge pin holes 18 can be minutelycontrolled to very close tolerances in the jig whilst the distancebetween the centers of the plugs 17 themselves is not critical and mayvary somewhat without destroying their effectiveness in the structure.Thusthe positions of the large'lateral holes 14 and 15 need not be heldto close tolerances, it being only necessary that the hinge pin holes 18be drilled through the central portions of the plugs and themselves heldto the required critical minute tolerances. A similar hole 19 is alsoformed through the plug 17 that is fixed in the hole-16 in the heelpart, it being also noted that Patented May 4, 1965 the enlarged holelo-need not be accurately positioned in the heel .part as thejack-thimble receiving hole 19 may be accurately positioned even thoughit is not axially located in the plug 17. A suitable metal jackreceivingthimbI-e 26. (-FIG. '4) is anchored inthe hole 19 of sleeves170 by any suitable fastening means, such "as sharp detents 21.

Upon completion of the hinge pin holes and the jack hole in the lastparts, routs 22 and 23 are formed in each last parttll and 12,respectively, for the reception of the last hinge hardware which maycomprise a hardened metal spring link 24 and two rub plates 25 and 26disposed on each side of the link. With reference to FIG. 3 it is to benoted that the formation of the routs cuts the drilled hinge pinreceiving sleeves 170 into two laterally spaced apart sections bothfixed in the last body on opposite sides of the routs. As most clearlyillustrated in FIGS.4 and the link 24 and the plates 25 and 26 arelocated in the routs and extend across the hinge knuckle 13 of theparts, one side of the link and plates being hingedly connected to thefore part 11 by a tapered pin 27 driven throughthe hinge pin hole 18 inthe sleeve 170 and through the link and through lost motion holes in theplates. A tapered pin 28 is then entered into the pin hole 19 in thesleeve 170 for the heel part and the tapered pin end is then forciblydriven through the hole in the link and 'throughlost motion holes in theplates in the heel part sides thereof to place the hinge under stressand hold the parts in strong over-center positions at their matingsurfaces. During the driving of the pins to their home positions acrossthe routs the severed sleeves serve to effectively reinforce the lastbody against collapse whilst the resulting last, although of lightweight, will be sufliciently mercially available asAmiloc, a product ofC. L. Rowe Corp. of Brooklyn, New York.

It was found that the completed shoe last formed from foamedpolyethylene compared favorably in weight to a Wood last of similarmass, was substantially the same weight as the comparable wood last butwas about lighter than solidpolyethylene lasts of comparable size andmass. I have found that a last formed in accordance with this inventionhas good nailing qualities and it was tested for strength and wassuitable as a form on which to manufacture shoes.

Having thus described my invention what I claim as new is: v

A collapsible shoe last comprising a forepart and a heel part havingmating, contact surfaces; said parts each having a cellular body formedessentially of foamed plastic material; a laterally extending holeformed through the body of each last part adjacent a contact surface; asleeve cemented in and fillingeach hole; said sleeves comprisedessentially of a non-cellular and stronger plastic material than thematerial of the last parts; a hinge pin receiving hole extendinglaterally through the central portion of each sleevegthe hinge pinreceiving holes in the sleeves being longitudinally spaced apart in thelast within accurately controlled, minute tolerances; confronting routsformed in thelast parts and throughthe sleeves; a last part connectinglink disposed in the routs and extending across the mating, contactsurfaces of the last parts; and a hinge pin positioned in each of thedivided sleeves and each pin connected to an end of the link.

References Cited by the Examiner UNITED STATES PATENTS 1,864,977 6/32Clarke 12-136 2,069,756 2/37 Glancy l859 2,165,006 7/39 Reinhardt 12-1362,330,260 9/43 Baxter l21'33 2,602,193 7/52 Korkatti 12133 2,678,2935/54 McMillan et al 12-133 JORDAN FRANKLIN, Primary Examiner.

RUSSELL Q'MADER, Examiner.

